1. Field of the Invention
The present invention relates to three-dimensionally structured warp knitted fabric for use in the clothing and non-clothing fields as cushioning and filling materials, and more particularly to three-dimensionally structured warp knitted fabric suitable for use as automotive sheet materials. Most particularly, the present invention relates to a three-dimensionally structured warp knitted fabric consisting of top and bottom substructures and yarns connecting these two substructures, which is produced on a double needle bed warp knitting machine so that the top substructure is a net texture with pores and the bottom substructure is a plain texture with no pores to provide it with optimal compressibility, air permeability and resiliency for its application in the above-mentioned fields.
2. Description of the Related Art
Various certain techniques have already been proposed as prior art for producing three-dimensionally structured warp knitted fabric consisting of top and bottom substructures and yarns connecting the two substructures. Such prior art three-dimensionally structured warp knitted fabric is mainly produced on double needle bed warp knitting machines so that the top and bottom substructures are interknitted with the yarns connecting the two substructures at either almost right or oblique angles, or at both angles to provide the fabric with a truss structure. Specifically, the three-dimensionally structured warp knitted fabric produced according to the prior art has focused its design on how to form a truss structure between its top and bottom substructures in order to enhance its compressibility, including how to cause the yarn connecting the two substructures to be intersected with them in order to prevent them from being shifted laterally from each other and what fiber material to use as the substructure connecting yarn.
As described above, the three-dimensionally structured warp knitted fabric conventionally available as prior art is designed focusing on its compressibility with its enhanced resiliency and recovery from compression strongly dependent upon formation of a truss structure between its top and bottom substructures, the use of fiber material of high elasticity as the yarn connecting the two substructures and other factors, especially the use of the substructure connecting yarn with a high density. Due to its above-mentioned structural design, the conventional three-dimensionally structured warp knitted fabric presents such a problem that when subjected to compression, it suffers bending of the high-density substructure connecting yarns, which causes them to be entangled with one another, resulting in extreme deterioration in its resiliency and recovery from the compression.
In addition, the three-dimensionally structured warp knitted fabric according to the prior art, if knitted with a net texture for either or both of its top and bottom substructures, causes a problem of the substructure connecting yarn protruding from the pores in the net texture and thus being subject to external abrasion, which results in trouble such as fuzzing of the yarn. As a result of such trouble, the fabric presents discomfort in use, deterioration in appearance and other problems.
The present invention was worked out in order to solve the above mentioned problems involved in the prior art. Specifically, it is an object of the present invention to provide a three-dimensionally structured warp knitted fabric which has higher compressibility and resiliency than its conventionally available counterpart, as well as enhanced abrasion resistance to prevent its fuzzing.
To solve the above-mentioned problems associated with the prior art, the inventors of the present invention have discovered that the conventional three-dimensionally structured warp knitted fabric principally consisting of three membersxe2x80x94top and bottom substructures and yarns connecting the two substructuresxe2x80x94can be modified by having these three members combined with a new additional member xe2x80x9cyarns controlling the substructure connecting yarns by handling, separating and holding themxe2x80x9d to minimize their bending and consequent entanglement that may otherwise occur when the fabric is subjected to compression, resulting in deterioration in its resiliency and recovery from the compression. The discovery of such substructure connecting yarn controlling yarns has led to the accomplishment of the present invention.
Therefore, the first aspect of the present invention provides a three-dimensionally structured warp knitted fabric consisting of a top substructure and a bottom substructure, either of which is a net texture, the other being a plain texture, and yarns connecting said two substructures with a plurality of yarns present between said two substructures and between said substructure connecting yarns adjacent to each other to control the substructure connecting yarns by handling, separating and holding them, said connecting yarn controlling yarns comprising points at which they are stitched into said plain texture side of the top or bottom substructure and portions where they are floating between the top and bottom substructures.
The second aspect of the present invention provides a three-dimensionally structured warp knitted fabric as specified in the first aspect of the present invention, wherein said substructure connecting yarn controlling yarns are arranged linearly, stitched into the plain substructure at given intervals in the wale direction.
The third aspect of the present invention provides a three-dimensionally structured warp knitted fabric as specified in the first aspect of the present invention, wherein said substructure connecting yarn controlling yarns are arranged in rectangular wave form, stitched into the plain substructure at given intervals in the wale direction.
The fourth aspect of the present invention provides a three-dimensionally structured warp knitted fabric as specified in the first aspect of the present invention, wherein said substructure connecting yarn controlling yarns are arranged in zigzags, stitched into the plain substructure at given intervals with the yarn stitching points as the turn-back of the yarn zigzag arrangement.
The fifth aspect of the present invention provides a three-dimensionally structured warp knitted fabric consisting of top and bottom substructures, either of which is a net texture, the other being a plain texture, with a course-wise cross-section wherein yarns connecting the two substructures have X-shaped intersections with yarns controlling the substructure connecting yarns arranged to hold down the intersections downward.
The sixth aspect of the present invention provides a three-dimensionally structured warp knitted fabric consisting of top and bottom substructures, either of which is a net texture, the other being a plain texture, and yarns connecting the two substructures at right angels to both substructures with yarns arranged floating and winding between the substructure connecting yarns, being stitched into the plain substructure at proper intervals, to control these yarns. The configuration of the three-dimensionally structured warp knitted fabric according to the present invention as described above serves to minimize the bending of the yarns connecting the top and bottom substructures caused when the fabric is subjected to compression, thus preventing deterioration in its resiliency and recovery from the compression due to the entanglement of the substructure connecting yarns resulting from their such bending.